When Brayton Simple Cycle gas turbines operate as mechanical power drive sources to electric generators and other mechanically driven devices, atmospheric air is compressed and mixed with hydrocarbon gases or atomized hydrocarbon liquids for the resulting mixture's ignition and combustion at constant pressure. To produce power, the hot combustion and working motive fluid gases are expanded to near atmospheric pressure across one or more power extraction turbine wheels, positioned in series.
The majority of Brayton simple open-cycle aero-derivative-style low nitrogen oxide emission (that may hereafter be referred to as Low-NO.sub.x) current art gas turbines are predominantly presently limited in achieving shaft output horsepower rating with 26% to 39% thermal efficiencies, whereas most simple cycle industrial-style Low-NO.sub.x art gas turbines are predominantly presently limited in achieving shaft output horsepower rating with 27% to 34% thermal efficiencies. The aero-derivative turbine higher efficiencies are achieved when the gas turbines operate with compressor ratios ranging from 14 to 35 and predominant first stage turbine inlet temperatures ranging from 2000° to 2300° F.
Existing gas turbines employ combustion chamber air/fuel combustion chemical reactions, wherein the elements of time and high peak flame temperatures increase the presence of disassociation chemical reactions that produce the fugitive emissions of carbon monoxide (that may hereafter be referred to as CO) and other chemical reactions that produce nitrogen oxides (that may hereafter may be referred to as NO.sub.x).
The best available applied turbine low NO.sub.x combustion technology for limiting gas turbine NO.sub.x emissions, using stiochiometric air/fuel primary combustion reaction chemistry means, still results in the production of NO.sub.x and CO that are no longer acceptable for new power or energy conversion facilities in numerous states and metropolitan environmental compliance jurisdictions. With the current art gas turbine's use of compressed atmospheric air as a source of oxygen (that may hereafter be referred to as O.sub.2) which acts as a fuel combustion oxidizing reactant, the air's nitrogen (that may hereafter be referred to as N.sub.2) content is the approximate 78% predominant mass component within the cycle's working motive fluid. Due to its diatomic molecular structure, the nitrogen molecules are capable of absorbing combustion heat only through convective heat transfer means resulting from their collisions with higher temperature gas molecules or higher temperature interior walls of the combustion chamber.
Despite the very brief time it takes for a current art gas turbine to reach a average primary combustion zone gas resultant temperature of less than 2600° F. within its combustion chamber, there are sufficient portions of the combustion zone gases that experience temperatures in excess of 2600° F. to 2900° F. for an ample period of time for the highly predominate nitrogen gas to enter into chemical reactions that produce nitrogen oxides. The same combined elements of time and sufficiently excessive high temperature permit carbon dioxide to enter into dissociation chemical reactions that produce carbon monoxide gas.
To achieve a goal of greatly reducing a turbine power unit's NO.Sub.x and CO fugitive emissions, it is necessary to alter both the fuel combustion chemical reaction formula and the means by which acceptable combustion chamber temperatures can be closely controlled and maintained within a power turbine unit's fuel combustion chamber assembly. Maintenance of an acceptably low selected fuel combustion peak gas temperature at all times and throughout all portions within the combustion chamber assembly, requires a change in the means by which the heat of combustion can be better controlled and more rapidly distributed uniformly throughout the gases contained within the fuel combustion chamber assembly.
To achieve a goal of significantly reducing a turbine power cogeneration system's mass emission rate of the “greenhouse gas” (otherwise referred to as carbon dioxide or that may hereafter be referred to as CO.sub.2) by a desired percentage amount, it is necessary to proportionally increase the thermal efficiency of a power cogeneration system which therein proportionally reduces the amount of combusted hydrocarbon fuel required to provide the energy conversion into a given amount of required work and usefully applied residual heat energy.
It has been well known and practiced for decades that higher humidity air and injected water or steam commingled with conventional air combustion gases increases combustion flame speeds and fuel combustion thermal efficiencies within gas turbines and other fuel combustion heater-burner apparatus using air/fuel combustion. It has also been well known and practiced that partially re-circulating combustion exhaust or flue gases containing carbon dioxide and water vapor back into a combustion chamber results in a reduced level of nitrogen oxides within the fuel combustion exhaust gases. Due to the high temperatures and speed of completed fuel combustion, the scientific community has been unable to reach a consensus as to precisely what series of altered chemical reactions occur when water vapor and/or carbon dioxide is introduced into a turbine combustion chamber.
Oxy-fuel combustion heater-burners have been employed for many years in the steel and glass making industries to furnish desired 3000+ degree Fahrenheit combustion gas temperatures into furnaces to avoid the production of high NO.Sub.x emissions (but at the expense of high CO emissions). Both the present air separation art methods' high energy costs of producing acceptable combustion grade oxygen, and the lack of devised combustion system methods to control preset desired oxy-fuel combustion heater-burner or combustion chamber uniform maximum temperatures, have curtailed oxy-fuel combustion applications within present energy conversion facilities.
Current art gas turbines must be de-rated from their standard ISO horsepower or kW ratings at ambient temperatures exceeding 59° F., or at operating site altitudes above sea level. Thus, during summer's peak power demand periods, when the ambient temperature can increase to 95° F., 12% to 18% horsepower derations of a conventional gas turbine's ISO rating can occur. It is obviously desirable that a power turbine/generator unit within a cogeneration system not be susceptible to such on-site ambient temperature derations when peak power demands occur.
The current and future projected increasing costs of purchased utility electric power and natural gas (or liquid hydrocarbon fuel) and the accepted projected future trend in the future of “distributed power” facilities, coupled with present and future environmental constraints on fuel combustion exhaust emissions, will make it commercially mandatory that such “distributed power” facilities have the combined attributes (at the minimum) of combined ultra-low NO.sub.x and CO exhaust emissions and substantially higher thermal efficiencies than offered by current art turbine power cogeneration systems. It can be expected that the number of new turbine powered ‘cogeneration system’ facilities in the world will be significantly greater than the number of turbine powered ‘combined-cycle’ facilities that are devoted purely to the production of electric power. The referenced ‘cogeneration system facilities’ are not new in concept. Such facilities became highly popular in the 1970's (then referred to as ‘Total Energy Plants’) and were aggressively promoted by many natural gas utilities. Reciprocating gas engine-driven generator sets were the predominant producers of prime power and utilized waste heat. These ‘Total Energy Plant’ facilities efficiently provided electricity, hot water or steam for domestic hot water and building heating requirements, and chilled water for air conditioning. ‘Total Energy Plants’ were widely applied to serve hospitals, universities, large office buildings or building complexes, shopping centers, hotels, food processing plants, multi-shift manufacturing and industrial facilities, etc. The 50 plus years old predecessor to the ‘Total Energy Plant’ concept was the central electric power and steam plants that continue to currently serve some large eastern U.S. cities, and more predominantly European cities and metropolitan areas. Predominantly, ‘Total Energy Plants’ and current cogeneration facilities have had less than 100 psig utility supplies of natural gas available to their facilities.